Body odor generally refers to a condition in which an unpleasant smell or a malodor is released from a body part or skin of a body part of a human subject. Although body odor is known to be influenced by various physiological conditions, it is generally related to perspiration or sweating of the subject, and the subsequent bacterial decomposition of the organic compounds present in the sweat which forms the malodor carrying volatile organic acids. It is therefore most common for body odor to develop at axillary regions of the body such as the underarm areas where a large number of sweat glands are located, although body odor may also develop at other parts of the human body such as the palms of the hands, the soles of the feet, the upper thighs and the back region.
Various deodorant compositions and/or preparations have been developed to reduce, alleviate, eliminate or mask the unpleasant smell, and/or to suppress or inhibit the production of sweat from the skin of the body parts. In general, the deodorants may work by providing an antiseptic effect to inhibit the bacterial decomposition; by incorporating an anti-perspiring agent to suppress or inhibit perspiration; and/or by introducing fragrance to mask the generated odor. Deodorant preparations may come in different forms, such as solid, gel, cream, liquid or aerosol for various applications such as apply-on or roll-on sticks or rollers, body sprays or even body wipes; and can be classified as a cosmetic or a pharmaceutical product depending on the specific active ingredients in the composition. A number of commonly used deodorizing actives include alcohols, triclosan, sodium stearate, ethylenediaminetetraacetic acid (EDTA), chlorhexidine and formaldehyde, etc. for their antibacterial function; and/or salts of aluminum or zinc such as aluminum chloride, aluminum chlorohydrate, and aluminum-zirconium compound, etc. as antiperspirants. In addition to these commonly used actives, hexamine, which is also known as hexamethylenetetramine or methenamine, is found to be a potent deodorizing agent, although its deodorizing mechanism is yet to be clearly understood. Nevertheless, hexamine comprising deodorant preparations have also been reported to cause skin irritation to the users, which may potentially relate to the release of formaldehyde from hexamine in use.